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Forensic DNA: Compromised Evidence

Biological samples collected from crime scenes, mass disasters, and missing persons cases may have been exposed to harsh environmental conditions such as heat, direct sunlight, and water that break down the chemical structure of DNA. Environmental exposure damages DNA by randomly breaking the molecules into smaller pieces. Inhibitors of the polymerase chain reaction (PCR), such as some textile dyes, can also interfere with the ability to recover a full DNA profile from biological evidence. New DNA tests are being developed to recover information from smaller regions of DNA, which are more likely to be intact following DNA damage. These new DNA tests include miniSTRs (using PCR primers close to the STR repeat region) and single nucleotide polymorphisms (SNPs). Whole genome amplification and DNA repair methods are also being evaluated to determine the possibility of enriching PCR amplifiable material from limited or damaged DNA templates.

NIJ-Funded Research

The table below shows NIJ-funded research projects. Select an award title to see details of the award, including any resulting publications.